The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools used with such drivers, the tools may also comprise screwdrivers, nut drivers, burrs, mounted grinding stones and other cutting or abrading tools. Since the tools may have shanks of varying diameter or the cross-section of the tool shank may be polygonal, the device is usually provided with a chuck which is adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore.
A wide variety of chucks have been developed in the art. In one form of chuck, three jaws spaced circumferentially, approximately 120 degrees apart from each other, are constrained by angularly disposed passageways in a body attached onto the drive shaft and configured so that rotation of the body in one direction relative to a constrained nut engaging the jaws forces the jaws into gripping relationship with respect to the shank of a tool, while rotation in the opposite direction releases the gripping relationship. Such a chuck may be keyless if it is rotated by hand. One example of such a chuck is disclosed in U.S. Pat. Nos. 5,125,673 entitled "Non-Impact Keyless Chuck" and 5,501,473 entitled "Chuck", both commonly assigned to the present assignee, and whose entire disclosure is incorporated by reference herein.
While many currently existing chuck designs have been successful, varying configurations are desirable for a variety of applications. Particularly, it would be desirable to have a chuck that could be manufactured with adequate performance for a lower cost than many currently existing chuck designs. For example, typically, the main body of a chuck of the type described in the above-referenced patents is manufactured from metal bar stock. Therefore, the greatest diameter of the chuck body at any point determines the diameter of the bar stock necessary to construct such body. Since bar stock is an expensive component of the chuck, design efforts have been made to minimize the diameter necessary to construct the chuck body which has typically necessitated use of separate thrust washers to receive the axial rearward thrust of the nut as well as separate rear sleeve members attached to the rearward section of the main body in chucks utilizing both front and rear sleeves. In addition, it is necessary to utilize secondary operations to place the oblique jaw passageways in the body and to create the main tool receiving bore. The most common way of forming these passageways and bores is through a drilling operation which necessitates the utilization of primarily round passageways and bores.